Feed regulator for machine tools



Nov. 5, 1935. H. ERNST ET AL FEED REGULATOR FOR MACHINE TOOLS f OriginalFiled Sept. 15, 1927 4 Sheets-Sheet l Nov. 5, 1935. H. ERNST ET AL2,019,487

FEED REGULATOR FUR MACHINE TOOLS I Original Filed Sept. 15, 1927 4Sheets-Sheet 2 amoentow #W 5 35 MM W Nov. 5,19%. H. ERNST ET AL FEEDREGULATOR FOR MACHINE TOOLS- Original Filed Sept. 15, 1927 4Sheets-Sheet '5 FEED REGULATOR FOR MACHINE TOOLS Original Filed Sept.15, 1927 4 Sheets-Sheet 4 Z7 6 LEE? I z-- 555555 2253"? L.

Patented Nov. 5,1935

UNITED STATES FEED REGULATOR FOR MAC TOOLS Hans Ernst and Lester F.Nenninger, Cincinnati, Ohio, assignors to The Cincinnati Milling MachineCompany, Cincinnati, Ohio, a corpora- 7 tion of Ohio 22 Claims. (Cl.90-215) This invention relates to machine tools and it deals moreparticularly with improved means -for effecting translation of anelement thereof,

and for varying and controlling the rate of trans- 5 *lation of saidelement.

More specifically stated this invention has for an object to provideimproved means for varying the rate of relative movement between acutting tool and a workpiece, to the end that the rela- 16 tive movementbetween the two will, at all times,

be effected at a rate best suited for machining the work-piece,notwithstanding the fact that the work-piece may be of such a nature orformation as successlvelyto present varying areas 15 or conditions tothe action of the tool or varying resistance to relative movementbetween the work-piece and the tool. A milling machine is a good exampleof a machine tool in which this invention may be em- 20 bodied toadvantage, the relative bodily movement between the rotating tool andthe translatable table 'afl'ording the feed, the rate of which is to bevaried and regulated. This invention will, therefore, be shown anddescribed in connection with a milling machine but it We understood thatit is equally adaptable to various other types of machine tools.

The utility of this invention will best be perceived by considering theresults attained there- 30 by in connection with a typical problem inmachining operations. Suppose, for example, it is desired to maintain .asubstantially constantpower consumption during the milling of the faceof a work-piece of T-shape and the feed is 35 in a direction lengthwiseof the T, it will readily be perceived that, due to the amount of metalto-be removed and consequently the difference in resistance to tablemovement, the feed rate may be substantially greater during the millingoff of that portion of the work-piece corresponding to the stem of the Tthan during the milling of the part corresponding to the cross-barthereof. This invention solves the problem presented by such a conditionby providing means for varying the feed rate in a predetermined cycle asmay be required by the nature of the work-piecet Any suitable orpreferred hydraulic system may beemployed for giving translatorymovements to the work table. For example a so-called closed system maybe utilized i. e.a' system in which fluid is drawn from 'one end of ahydraulic motor and injected into the other end thereof, the rate ofmovement being determined 5 by the rate at which the fluid is injected;or the so-called metering system" may be employed,

1. e. one in which fluid is forced into one end of a hydraulic motor andthe rate of movement of the piston and its connected parts is determinedby the rate, at which fluid is removed from the exhaust end of the motoras by means of an escapement device. A system of this latter type isclearly disclosed in our pending United States patent application,Serial No. 220,721, filed Sep- 1 tember 15, 1927, of which thisapplication is a division.

Another object of this invention is to provide improved adjusting meansbetween the hydraulic motor and the work-table actuated thereby, wherebyrelatively small feeding movements may be given to the work-tablemanually independent of the action of the hydraulic system.

The objects of this invention have been attamed by the embodiment, in amilling machine, ofi, a hydraulic motor connected to reciprocate thework-table. Reciprocatory movements are given to the motor and to thetableconnected therewith by a continuously acting variable displacementpump adapted through suitable adjustments to pass fluid at any rate fromzero to maximum. The pump is connected with the hydraulic motor and therate of movement of the work-table is determined by the rate at whichthepump passes fluid, preferably oil.

The variable pump selected for a practical embodiment of this inventionis of that type comprising a laterally shiftable cylinder blockproviding a plurality of radially disposed cylinders within each ofwhich a piston is slidingly fitted. A rotatable casing surrounds thecylinder block and provides an annular wall engaging the outer ends ofthe pistons. When the axis of the easmeans for varying the position ofthe cylinder block relative to the casing element in accordance with theshape, area, or quality of the workpiece being machined.

For quantity production, 1. e., where a substantial number of likepieces are to be machined successively, this invention proposes toprovide automatic means for shifting the pump successively to vary itsdisplacement in a predetermined cycle as may be required to effect thefeed at the most efiicient rate for every portion of the work-piece. Onemeans for accomplishing this result comprises a cam, fixed totheworktable, and translatable therewith, and a cooperating elementtracking said cam and being up- "eratively connected with the laterallyshiftable pump casing. Thus by the formation ofthe cam the pump may becaused to pass fluid at any available rate between zero and maximum.

Means also is provided for discontinuing the action of the automaticcontrol and for plac ing the pump under manual control.

Other objects and advantages will be in part indicatedin the followingdescription and in part rendered apparent therefrom in connectiomwiththe annexed drawings.

To enable others skilled in the'art so fully to apprehend th derlyingfeatures hereof that they-may embo picting a preferred typicalconstruction have been annexed as a part of this disclosure and,

in such drawings, like characters of deference denote correspondingparts throughout all the views, of which: I

Figure 1 is a side elevation of a milling machine embodying thepresentinvention. Fig.

2 is a detail view, partly in section of a portion ofthe millingmachine, the pump unit for effecting the table feed, and the automaticvariator for the variable displacement pump'. Fig.

3 is a vertical section through the pump unit taken substantially on theline 3-3 of Fig. 2

Fig. 4 is a horizontal section through said unit.

Fig. 5 is a detail sectional view showing a hand adjustment for movingtheworktable relative to a the piston rod. Fig. 6 is a diagrammatic viewrepresenting a hydraulic syste'iiijto which the present regulating meansis adaptable. and Fig. 7i

is a detail view of a prefeiredform of mechanism for controlling, thevariable pump from the cam carried bythe work-table. Fig. 8 is anelevation of a portion of the mechanism shown inFig. 7. Referring morespecifically to the drawings the invention is disclosed as embodied in amilling machine comprising a base A, translatable workv table T,. androtating tool spindle S; journaled in i a head H, adjustably supportedupon a standard K,'rising from the base.

# The hydraulic system utilizedfor effecting re-v ciprocatory. movementsof the table 'at feed and traverse rates is illustrated diagrammaticallyin Fig. 6 and comprises a cylinder I fixed to the base of the machine; apistohhfitted within the cylinder and connected with the worktable bymeans of a piston rod 3; a suitablelow pressure high capacity pump Radapted to eifect traversing movements of the table; a high pressurebooster pump B, and a variable displacement pump V connected with thecylinder by conduits y and z. Fluid (preferably oil) for use in thesystem is obtained from a reservoir F located within the machine baseand the'direction of the flow of fluid through the system, therev thesame inthe various ways 30 contemplated by this invention, drawings" de-2,o 1a,4a7

by determiningthe direction of movement of the table, is controlled by amaincontrol valve L.

Briefly stated this valve is adapted to connect the continuously runningrapid traverse pump witli either end of the cylinder I andsimultaneously therewith to connect the opposite end of the cylinderwith the reservoir, whereby the table '1' is given rapid traversemovements in either direction. It also serves to connect'the rapidtraverse pump with the reservoir when rapid move-. 10 ment of the tableis not desired.

The valve is alsoadapted selectively to connect the intake port of thevariable displacement pump with either end of the cylinder andsimultaneously therewith to connect the exhaust port 15 thereof with theopposite end of the cylinder to I eifect slow feeding movements of thetable in either direction, The booster pump receives fluid from theexhaust'line of the rapid traverse pump and injects it into the exhaustline of the variable go delivery pump thereby maintaining a high pres-"sure on the intake end of the hydraulic motor.

The rate at which the piston 2, piston rod 3 and table T are moved.under the influence of this high pressure is determined by the rate atwhich 25 fluid iSs. removed from'the opposite end of the motor by thevariable displacement pump which functions as a metering,.o'rescapement, device. For certain purposes it is desirable to lock thetable against movement in either direction. This 3 may be accomplishedby means of an auxiliary valve'M adapted to isolate the pumps from thehydraulic motor andto trap the fluid in the motor at opposite ends ofthe piston. With both ends of the cylinder fllledwith oil, which has nomeans 35 sary. i

v To afiord manual means'for giving the table slight reciprocatorymovements relative to piston rod while the latter is locked againstmovement, 5

the piston rod is connected with the table 3! shown in Fig. 5. Thisconnection comprises a.

threaded end 3* of the piston rod and a comp'lemental nut 4 rotatablyjournaled in a lugt depending from the table. Ahand wheelihavlng so itshub 5 pinned to the-nut 4, affords means for rotating the nut on thescrew. A flangs l" on the nut I engages one face of the lug t and thehub 5* engages the other face thereof. The nut is thereby held againsttranslation relative test the table, and rotation of the nut on the stationary screw eifectstranslatory movement of the nut and table.

The variable escapement mete device Mitch regulates the rate at whichfluid is ejected from do the feed cylinder may be of any suitable ordesired construction. There is shown in Figs. 2, 3

and 4, one form of device which accomplishes this result satisfactorily.This device consists. of

a variable displacement pump of that type comas prising a non-rotatingcylinder block I provided with a plurality of radially disposedcylinders withineach of which is slidingly fitted apiston I.

A rotatable casing element 8 fixed to a shaft 0.

driven by a gear l0, surrounds the piston block 10 and is formed withan'annular wall ll adapted to engage the outer ends of the pistons. whenthe axis of the cylinder block and the axis of the casing element arearranged eccentric to eachother and the casing element 8 is rotated the15 wall H of the casing element alternately forces inwardly on thepiston I to eject from the (817 inder the fluid which previously hadbeen admitted thereinto during outward movement of the piston. When theaxes of the cylinder block and the casing 6 are concentric the pumppistons are maintained non-reciprocable and pump displacement is atzero. It'will therefore be perceived that the rate of delivery of themetering device is determined by the relative positions of the axes ofthe cylinder block 6 and the casing B. To provide for varying therelative positions of these two elements thereby to vary the rate ofpump delivery, the cylinder block is supported by a rock arm l2journaled upon a pintle l3 fixed in the casing P of the pump unit.

A feature of this invention resides in the provision of means forautomatically changing the effective action of the meteringdevice-during unidirectional movement of the work table whereby thetable may be caused to move at varying rates to provide a feeding ratebest suited for machining a work piece having a surface of varying areaor offering varying resistances to table movement. To that end there isjournaled within the casing P a shaft l4 and upon which is secured aneccentric l5 which engages a roller I6 carried by the free end of therock arm I 2. A plunger rod l8 reciprocable in bearings I 9 and 26carries a circular rack 2| which meshes with a pinion 22 on the shaftl4. A coil spring 23 interposed between the bearing l9 and a collar 24on the plunger rod normally serves to elevate the plunger rod andthereby rotate the pinion 22 and eccentric element l5 to a positionwherein it puts the arm l2, in opposition to the action of a spring 25,to a position in which it effects maximum pump displacement. Upon thereciprocating work-table T there is secured a cam 26, the face of whichengages the upper end of the plunger rod l8. Upon reciprocation of thetable, the cam will act to depress, and to permit to elevate, the

plunger bar is which through the parts previously described will effectthe swinging movement of the arm l2 to increase or decreases theeccentricity of the cylinder block 6 with respect to the casing 8,whereby to vary the effective action of the metering device andconsequently varying the rate of table feed. It is to be understood thatthe cam 26 will be formed in accordance with the form and nature of thework piece to be machined or the resistance to table movement offeredthereby and that this feed regulator will be used primarily for quantityproduction.

Manual means is provided for throwing out the automatic control for thevariable displacement pump. This means comprises a shaft 21 journaled incasing P and an eccentric 28 aflixed thereto and engaging the upper sideof the collar is. A crank 29 afiixed to the outer end of the shaft 21serves to rotate the shaft and eccentric either to the position shown inFigs. 2 and 3, in which the eccentric acts upon a collar 22 anddepresses the plunger bar IE to its maximum extent, or 180 therefromwhich permits the plunger it to move upwardly to its maximum extent. Aspring pressed plunger pin 36 carried by the crank 29 is adapted to beinserted in either one of two apertures 3| provided by the casing P.

A manual adjustment of the variable escape ment is also provided forvarying the feed rate. This comprises a shaft 32 journaled inthe casingP, in alignment with the shaft it, and an eccentric element 33 securedthereto adjacent the automatically actuated eccentric IS-previouslyreferred to. The eccentric 33 also engages the roller I6, and uponrotation of the shaft 32 acts to swing the arm l2. A hand crank Q fixedto the shaft 32 affords means for rotating the shaft, 5

and a spring pressed pin 34, carried by the crank, is adapted to enterany one of a plurality of apertures 35 provided in the casing P, therebyto maintain the parts in any desired position of adjustment. It is to beunderstood that this 10 manual control will be used when the automaticcontrol, including the cam 26, is rendered ineffective by the action ofthe feed throwout above described.

Any suitable means may be provided-for continuously actuating the rapidtraverse pump R, the booster p'ump B and the variable displacement pumpV, all of which are embodied in the casing P. For example, the traverseand booster pumps may be actuated from a common shaft 90 36, journaledin the casing of the pump unit, which shaft may be rotated from a maindrive motor through a train designated generally as m. A gear on theshaft 36 may mesh with the gear ID on the shaft 9 of the variable pumpto effect 35 rotation of the pump casing element 8 above described.

It is to be understood that the variable pump controlling-cam 26 isremovably secured to the work table T and that it may be removed and 30replaced by another cam of different contour to produce a differentfeeding cycle as may be required by any work-piece.

A preferred form of mechanism for connecting the feed control cam 26with the pump varying s5 eccentric I5 is disclosed in Fig. 7. Thismechanism is similar to that illustrated in Figs. 2, 3 and 4 to theextent that it also includes a shaft id to which the eccentric member I5is secured and that said shaft is provided with a pinion 22 m whichengages a circular rack 2! provided by a vertically movable plunger bar,or slide-rod, is. It differs from the form previously described in theconnection between the slide rod and the feed cam. In the preferred formthe effective face 45 of the cam 26 engages a contact point 40 providedby an arm 6| rotatably mounted on a shaft 42 journaled in a bearingbracket 3. The arm M has a laterally projecting portion 44 carrying anadjusting screw 45 which rests upon one arm Q6 (forming a. part of whatin effect is a two-armed lever 46) fixed, as by a pin 61, to one end ofthe shaft 42. The other arm 88 of the two-armed lever is fixed to theother end of the shaft and has its free end formed as a toothed segmentwhich engages a circular rack d9 formed on the upper end of the sliderod l8. 7

In this preferred form the coil spring 23, surrounding the slide rod I8,is interposed between a collar 50 pinned'to the slide rod and a fixedlug 5| provided by a supporting bracket 52. Thus the spring normallyacts to depress the rod and thereby through the lever arms 68, 46 and Mto elevate the contact point 40 to maintain it in engagement with theeffective face of the feed cam 8t one or more of the features that, fromthe stand- 76 characteristics of either the'generic or specific aspectsof this invention and, therefore, such adaptations should be, and areintended to be,

comprehended within the meaning and range of equivalency of thefollowing claims.

Having thus revealed thisinvention, we claim as new and desire to securethe following combinations and elements, or equivalents thereof, byLetters Patent of United States.

1. A machine tool combining a rotating cutter; a work table movablerelative thereto; hydraulic means for feeding said work table; avariable controlling means fordetermining the rate offeed of said tableunder the action of said hydraulic means; a cam carried by saidwork-table and bearing a definite relation with a work piece on saidtable; and means constantly under the control of said cam for varyingsaid controlling means thereby to determine the feed rate of said tablethroughout a uni-directional movement thereof in accordance with thework-piece.

2. A machine tool. combining a reciproeable work table; hydraulic meansfor reciprocating said table, said means including a cylinder, a pis-'ton reciproeable in said cylinder, one of the last named members beingstationary and the other connected with thereciprocable table; means toadmit fluid pressure into one end of said cylinder; a variableescapement means for permitting fluid to be exhausted from the other endof the cylinder in measured amounts thereby to determine the rate offeed of said table; and means actuated in timed relation with themovement of the table and during a uni-directional movement thereof forvarying the action of said escapement device and thereby the rate oftable feed.

means to vary. the feed rate; and means to render said automatic controlmeans ineffective.

4. A machine tool combining a reciproeable member, hydraulic meansincluding a hydraulic motor and a :irariable delivery pumpconnectedtherewith to reflect reciprocation of said member at varying rates, saidpump including: a shiftable element adapted in its various positions toeffect pmrrp deliveryat varying rates; automatic control\means for saidpump including a pattern camfmovable in timed relation with said reciperocable member and an element actuated by said cam and connected to movesaid shiftable .element to vary the rate of pump delivery and therebythe feed'i'ate of said reciproeable member; means to render saidautomatic control means ineffective; and manual means operablethereafter to control the action of said variable delivery Pump.

5. A machine tool combining a reciproeable member, hydraulic meansincluding a hydraulic motor and a variable delivery pump connectedtherewith to effect reciprocation of said member, said pumps including ashiftable element adapted by its various positions to vary the rate ofpump delivery from zero to maximum; means normally action of said cam onsaid lever effects, through a019,? point of the prior art, fairlyconstitute essential tending to hold said element inone of its extremepositions; an eccentric device engaging saidshiftable elementand'adapted to vary its.

position; a plunger bar; a rack and pinion connection between saidplunger, bar and said ec- 5 centric device; a feed controlling camcarried by said reciprocable member; a lever actuated by said cam; and arack and pinion connection between said lever and said plunger bar,whereby 10 said rack and pinion' connections and said 'plunger bar,pump-varying adjustments of said eccentric device. 4

6. A machine tool combining a translatable work table, an hydraulicmotor connected with 1 said table; a reservoir containing fluid; a highcapacity low-pressure pump adapted to draw fluid from said reservoir anddeliver it into said motor to effect rapid traverse of said work-table;a high pressure pump adapted to receive fluid from said go reservoir anddeliver it into one end of said motor to effect. movement of said tableat a feeding rate; a variable delivery pump adapted to be connected.with the discharge end of said motor to control volumetrically the rateat which fluid is discharged therefrom thereby to regulate the rate atwhich the table is moved by said'high pressure pump; a cam bearing adefinite relation with a workpiece carried by said table; and con trolmeans relatively movable with respect to said cam and constantly under;the influence thereof for varying the effective capacity of saidvariable delivery pump thereby to determine the rate of feed of saidtable during an entire feed movement.

7. A machine tool combining a work-table; an hydraulic motor connectedwith said work-table;

' a reservoir containing fluid; a high capacity low pressure pumpadaptedto draw 'fluid'from said reservoir and deliver it. into said motor toeffect rapid traverse of said work-table; a high pressure pump adaptedto receive fluid from said reservoir and deliver it into one end of saidmotor to effect movement of said work-table at. a feeding rate; avariable escapement means connected. to the other endgof said motor toregulate the rate at which fluid is discharged therefrom, thereby todetermine the rate at which the table is fed under the influence of saidhigh pressure pump; a pattern cam bearing a definite relation with aworkpiece carried by said work-table; and control means relativelymovable with respect to said cam and constantly under the controlthereof .for varying the action of said escapement means thereby todetermine the rate of feed movement of said table under the influence offluid delivered by said high pressure pump. I 7

8. In a machine tool, a translatable work-table; an hydraulic motorconnected therewith; means for admitting relatively low pressure fluidinto 00 said motor at a relatively fast rate to effect rapid traversemovement of said work-table; means lg admitting relatively high pressurefluid into said motor at-a relatively slow rate thereby to effectfeeding movements of said table; valve means for 05 selectivelyrendering effective said rapid traverse and feeding rates; variablecontrolling means for varying the feeding rate of said work-table inaccordance with a workpiece carried thereby, said means including avariable feed rate controller, a 7 pattern cam coextensive with andbearing a definite relation with the workpiece and movable with saidtable relative to said controller, a cam engaging element, and a directconnection between said cam engaging element and said controller wherebythe controller is actuated by and maintained constantly under theinfluence of said cam during a feedingmovement,

9. A machine tool combining a. reciprocable member, and hydraulic meansfor reciprocating said member, said means including a hydraulic motorand a variable displacement pump connected therewith, said pump having ashiftable element movable to effect increases and decreases in the rate01' pump delivery and thereby the rate of movement 01' said reciprocablemember, a cam having a contour varying in accordance with the variabletooling requirements for machining a selected'work-piece, powertransmitting linkage connectible between said cam and element, meanseii'ecting relative movement between the cam and linkage incorrespondence with the movement of the reciprocable member, and meansto maintain the cam, linkage and element in constant power transmittingengagement during said relative shitting, whereby the cam contour reactsdirectly on the pump incrementally and decrementally to regulator; and amanual limit stop for control its eflective delivery during the toolingoperation. v

10. A machine tool combining a reciprocable member; hydraulic means forreciprocating said member, said means including a hydraulic motor and avariable displacement pump connected therewith, said pump having ashiitable element adapted in its various positions to vary the rate ofpump delivery and thereby the rate of movement of said reciprocablemember; means normally tending to shift said element to one of itsextreme positions; an actuator element mechanically connected directlywith said shiitable element; a variably contoured cam engagingcontinuously said actuator element, said actuator element and cam beingmounted for relative movement by the movement of said reciprocablemember to shift said actuator element and'thereby to operate directlythe shiftable element of the pump to vary the delivery rate 01' saidpump incrementally and decrementally in accordance withthevaryingcontour of saidcam.

11. A machine toolcombining a work carrier; a tool carrier; hydraulicmeans embodying a variable rate pump for propelling one of saidcarriers; a regulator varying the rate of said means; an automatic tripoperated by one of said carriers and having a lost motion connectionwith said varying the amount of said lost motion.

12. A machine tool combining a reciprocable work table; hydraulic meansto feed said table, said means including a cylinder, 8. piston therein,one of which is connected with the table, and

'means to admit fluid pressure into one end of said cylinder to efiect arelative movement be-'- tween the cylinder and piston; variableescapement means connected with the exhaustend oi the cylinderpositively a limit the rate 01 exhaust thereby to determine the rate offeed of said table; automatic means for controlling the escapement meansto vary the feed rate; means to render said automatic control meansineffective; and manually actuated means, operative when said automaticmeans is rendered ineffective, for controlling the escapement means,thereby to vary at will the rate of table feed.

13. A machine tool combining a workcarrier; a tool carrier; hydraulicmeans embodying a variable rate pump for propelling one of saidcarriers; a regulator varying the rate of said means; an automatic tripoperated by one of said carriers and having a lost motion connectionwith said regulator; and a manualthrow-out for rendering I saidregulator inoperative.

' a 14. In a machine tool, the combination of a movable member, atransmission therefor including an adjustable rate changer and an 9181'ment driven therethrough, means automatically operable in accordancewith the movement of said element to adjust said rate changer, wherebyto maintain the rate of said member substantially at a predeterminedvalue, and means aliernatively adjustable for said automaticallyoperable means to be operative or inoperative.

15. In a machine tool the combination of a movable member, atransmission therefor including a hydraulic portion and an elementdriven therethrough, said hydraulic portion being in part adjustable tochange the rate of movement of said member, means automatically operablein accordance with movement of said element to adjust said adjustablepart, whereby to substantially maintain any desired rate of said member,and means alternatively adjustable for said automatically operable meansto be operative or inoperative.

16. In a machine tool the combination of a movable member, atransmission therefor intrain driven from said spindle transmissionfor'movement of said work support and including a fluid operable portion inpart adjustable for changing the rate of movement of said work supportand also including an element driven through said fluid operableportion, and means automatically operative to adjust said portion.

18. In a machine tool the combination of a movable support, atransmission for movement thereof including a fluid operable portion inpart adjustable for changing the rate of support movement, a. firstmeans shiftablefor adjusting said portion to a position approximatelypro- \ductive of a desired rate of support movement, other meansshiftable independently of said first means for additionally adjustingsaid portion,

. and means for shifting said other means in accordance' with themovement of said support.

19. In a machine tool having a movable support the combination of atransmission for movement thereof including a fluid operable portion inpart adjustable for changing the rate of support movement, a poweroperated shifter for adjustment ofsaid portion, and a control device forsaid shifter including a member manually shiftable to a variety ofpositions, and a member shiftable in accordance with movement of saidsupport, said device being operative in accordance with the relativeposition of said-members.

20. In a machine tool, the combination of a movable member, atransmission therefor including adjustable rate change means, manualmeans for adjusting said rate change means to approximately predeterminea desired rate, other means for further adjusting said rate change meansin accordance with changes in some of the operating conditions of saidmachine tool, and control means alternatively adjustable for selectivelypreventing or permitting the adjustment of said rate change means fromsaid other means.

21. In a machine tool, the combination of a movable member, atransmission therefor including an hydraulic motor and an adjustablepump connected for operation of said motor, manual 10 means foradjusting said pump, other means for a,o19,4s7 1 ting the adjustment ofsaid pump from said other means. n

22. In a machine tool, the combination of a movable member, atransmission for movement thereof including a fluid operable portion ofpart adjustable to change the rate of support movement, a manual meansmovable for adjustment of said portion to select a desired rate ofsupport movement, and other control means operative to adjust saidportion to effect the desiredrate of support movement in spite ofvariations in the operating conditions of the machine;

1 HANS ERNST.-

LESTER F. NENNINGER.

